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A ug. 27, 1929. C, PLATT 1,726,503

THERMAL CUT OUT Filed Aug. 9, 1926 Fi 2- 12 '-g- 9 HIM 23 5% 7 Patented Aug. 27, 1929.

YUNTED STATES CLARENCE D. PLATT, OF BRIDQEPORT, CONNECTICUT, ASSIGNORITO THE TRUMBUIAL ELECTRIC MANUFACTURING COMPANY, OF

RATION OF CONNECTICUT.

'tion or infany other construction in which such fuses may be used. y

Another object is to provide an automatic cut out which is so compact that it occupies no more space than is required for a stand# ard cartri e fuse plus the necessary clearanco spacing as required by the underwriters.

Another object is to provide .an automatic cut out from which magnets, solenoids, re-4 lays, auxiliary contacts and circuits are entirely eliminated and the cut out may be placed in foperable position4 by merely inserting its terminals (errules) into aI pair of standard fuse clips. l 1

Another object is to provide an automatic cut out which is self-contained' and may be reset but which does not requireiany fuse or renewable elementA inorder :to reset it.

Another object is to provide an automatic cut out in which the metallic operating parts are entirely enclosed and which may be reset withoutthe use of tools of any description and without necessitating the touching' of any metal or current carrying parts.

`Another object is to provide an automatic, cut out which will open the circuit at a prei determined point of overload but which will have a time lag element operating-to'prevent the immediate latching of the switch contacts after the load.

Another object is to provide van automatic' cut out constructed of standard parts and in which the different points of calibration` may be pre-determined by using diferent sizes of one of its element-s. Another object is to provide an automatic cut out having a standard form of switch blade and contact which operate as a current carrying quick break switch.

Another object is to provide an automatic cut out with a thermostatic latching means which is operable without affecting the current carrying capacity of the parts at any stage of operation.

switch has operated on @ver-` PLAINVILLE, lCONNECTICUT, A CORPO- cut out 'of such simplen oin'pcty fand yfunderstandableform that any, ,oi/ie may. substitute it for an old :type'flse ini any,""'stax'1dard electrical construction an'ldtlius thereafter. save the costof afuvsee litiin'e' 'thecut out operates'- i. 21M! rw Another .object "is to?r an automatic cut out which thefo'allbratin' orop'erating point is detegming la'tjtlh'fiitify andthe operating partsare tlinrcovered-,and sealed against ltam'pe'rin with orfhanging i by the careless'fuserifsic 'fcn'ns'truction also acts'as a safety v'varnix'fg "or` `l anger 'signal and will prevent theuhinteiitiqiial overloading of the circuit. ffgf y l ,Referriiig :to the accompanying drawings z clips'.

Fig. l5 shows an exploded v iewof the w'rkmgpafts er the* device 1 i y 'Similar lrefere1ic` finerals 'are "applied to The switch blade Gfis supported uponthe metallic block 7fb`y`the1`s'cew' '8 about which itmayswing. l:This block 7, is'fsecured to the body ofthei device by thescrewgwhich in turn lholdsjth'e4 |te'rrninalcap 10 firmly into its cradle or 'seat "11 beneath the body. The spring 12`whose helical' portion lsurrounds .the `screw8.by bearing 'against' thel insulating handle '5;A and the wall of the container 1 tends to 'force the switch blade 6 in' counter-clockwise direction *causing it to break contact with the switchjaws '13. This is normally prevented' when""the `device' is set, by the ear 14 engaging'the'endof'the strip 15. This strip" 15 is prefera'bly made of bi-metallic'thermostati metall and 4,is se` cured along with'tthe vswitch jaws 13 to the:

angular bracket 161by thentubularnrivet The bracket 16 and attached members are secured to the body by a screw 18. One

the bracket. by 'the rivet20. 'E'Ihe iother'r end is connected to the terminal cap 21 by the screw 22 which passes through thc'plate'23 and the insulating body,. 'Lheterminal caps and 21 correspond'inv siz"and"spacing with.. the .usuali females, of a. cartridge ,type fuse.' Sb 'that they. 'arenterchaneabl teeny standard.apanage',

It' will be'fseen'tha'tfthis ltlrupcoil 1Q e its .normal posiftiontbe 4deuice,nrayb'e ,reset It will also be seen that Withoutvchapgieg the denensioeentanraefehe pantsief this devine,-WitltthQXRtOa 9fthe beatingfcefLL?, be, made-te Qperate at. any

predetermined value of current within a f wide range.l

It will also vi'ialue at, which ,the device operatesmay be changed by substituting f orthe 'stripilv anothergstrip.

of thermostatic material orfdiifering warp ing modulus, or again by, Naryjng the ,depth of ithe face vof the ear A14e., e

Itv will: be, noted thatwhen the circuit is QlOSed thecur'rent, passes through this device. from terminal cap: to, terminal, cap, through relatively stationary 'part-s and, although some.v ofthe 'current may in the. form shown flonT through the. `,bifmetallic latch when the circuitisclosechl the mainecircuit is not atall affected. bythe slow moving latch or'by the snapping away movement of the switchbladeaOm .the latch. because the actual circuit breaking moment vdoes not come until the switch blade is :leaving the A, Contact jaws, thus the circuit is broken entirely.- by the blade. 6 snappingquickly away from the Vstationary Contact 13 in contradistilnction tothe separation vrot slow moving thermostatic elements.- .l

To cause the operation of the thermostatic latch .by means of an adjacent heater coil provides for.avaluablefti1ne lag lfeature in that, after the opening otthecircuit, the coil remains vinv a; heated.. condition.. long l enough. to. prevent the relatchinggsof; the lswitch in closed position for an appreciable time,1 Whereas, a iiimetallic thermostatic member cools and returns to its normal condition comparatively very quickly.

4A=feature of: particular value in this con struction 'is that the nature ofthe parts and the arrangement v.ofthe-same is such that Vthe-device can actually be so reduced in size `that it may be commercially produced and substituted, in use, for the common 30 amp.

,250 lrv. lenclosed -uses Without any change in. theuse clips or their standard spacings. The' 'heater' element, the thermostatic latch and 'the' functonstheyperform' areof such a naturev that litis ,possible to commercially produce accurately: calibrated Acutiilts which n1aybe'-rdepended-upon to automatically operate 'at' the predetermined point and which pointmayeasily be varied from lone to thirty amperes to'confo'rmpto standard practialef'gteilrse the' relays may be bfeither larger or" smaller 'relative size or capacity.v

' llQAn'elctrfi'c cutfoutfcomprising an insulating. body having vrecess in'l the front, a ,p'i'voted bladelfa :thermosta'tic latching ineanscoa 'ting'drectly therewith and a 'separate' heat lement for Asaid means all mountedzin `aidfrecesS, ,an 'insulating covci for 'terminal caps at! the rear of 'oppfosite ends :of said'bodyelcctrically connected'respectively -to the s t'v'itcli blade andftdon'e' 'termina-l,of-thel latching means, said' terminal caps being adapted to. be inserted inrstandarduse clips positioned .1t standard y MZAnQelectricrf tr-out.` comprising an insuelating bodyghalvin'gca recess, a movable snap switch blade,a' bm e`tallic thermostatic latch .having direct. operable =engage ment with syvitchl blade, =a separateheating element forsaidlat'chmounted in said recessand terminal caps at .opposite ends: of said body electrically'connected respectively to.the movable switch blade and to the heater element for said-latch, said cut-out being adapted to be,inserted in standard cartridgetype fuse clips. l

3.-An.electric cut-out comprising an in sulating body having a recess in the front, a pivoted snap switch blade mounted in saidA recess, a terminal cap .exterior to said body and connected to said switchblade, a stationary switch Contact in said recessadapted to be engaged by said pivoted switch blade, a thermostatic element having a direct latching engagement with the switch blade, a heater element adjacent said thermostatic elementin said recess and having one end electrically connected to thes-stationary switch contactand an exterior terminal cap connected to the Vother end of said heater element.

4. An electric cut-out comprising a body: having a recess, a cover forsaldreccss, af

bracket mounted in said recess, a stationary switch contaet and ax thermostaticl latchl secured to said bracl{et,'.fa'!heat`ei element adjacent to andwith one end connected to said bracket, a movable lswitch member in said recess l coacting 'with the stationary s'witch contact and exterior lcircuit terminals secured to said body and'electrically connected respectively'fto saidmovable switch member and tofthe'other end of said heater element.

5.1An electric cut-out comprising a'body having'arece'ss, acover 'for' said recess,fan electrie'switch bladefa thermostatic latch strip and' a heater coill mounted in said recess adjacent to said strip, thetip of said strip I serving to directlyenga'gethe- 'switch' blade in the' closed :,circuit' positioni under normal Conditions f and.' said'v coil being 'arranged to heat' 'andf 4bend :the thermostatic element to release the siv'ritcli under predetermined conditions-"and:circiitlterininals on the outside of said bddyr electrically' 'connected 'respecltivelj'ttlie s'witliblade and ithe heater Ecoil.`

"6.' Inan electricffcut-outan insulating housing comprising -a' body and a cover, ter-` blade, a pair of Lswitch" jaws, 'a thermostatic switch latch anda heatingi element forsaid latch,g all mountedfinisaid recess, said latch having direct engagement with said switch blade and being influenced byy said heating element to release said blade prior to the opening of the circuit, and two terminal caps mounted on the back of said body, one being electrically connected to said heating element and the other being electrically connected to said switch blade.

8. An electric cut-out comprising an insulating body having a recess, a bracket mounted in said recess, stationary switch jaws and a bi-metallic thermostatic switch latch secured to said bracket, said latch having a movable end, a heater element connected to said bracket and positioned adjacent said latch, a pivoted switch blade in said recess to engage said switch jaws and coacting directly with the movable end of said latch, a spring tending to disengage said blade from said jaws and latch, and exterior circuit terminals secured to said body and electrically connected respectively to said movable switch blade and to said heater clement. c.

9. An electric cut-out comprising a body having a recess, a pivoted switch blade, a stationary contact to be engaged thereby, a bi-metallic thermostaticlatch land a separate heater element mounted in said 1,rece'ss'behind said latch, said latch-serving to ydirectlyiengage the switch bladeand hold it in the closed circuit position under4 normal conditions, a spring tending `tof-disengage said switch blade and said heater element being arranged to heat thethermost-atie latch, thus causingfit to warp and release `'theswitch blade at a predetermined vcircuit condition, and two terminal caps' on the outside oflsaid body electrically connected: respectively lo the switch blade and to the heater element? 10. "A device-to replace fuses ofv the'standard 30 amp., 250 volt:-cartridgef'typeandl consisting of-'an` insulating-body wi'thexterior 'conducting terminals secured thereto, theidimensions 'and relative positions of said terminals beingvsubstantially those of-stand ard -30 amp., 1S250'volt fuses, ai spring opened switch blade adapted to- A be latched 1in" `the closed "circuit' position, a thermostatic strip directly engagingrsaid blade,l;a heating element positioned so as to-heat'said strip and cause -it to',l warp and -unlatch Asaid switch blade at, af 'predetermined circuit condition,- said switch blade ya'n'd'said'heating element' beilng connected inseries between said'terminas. 1f i :11. 'An electric'. cut-out-oomprising a rectangular :body having 1a lrecess-in lthe v'i'ront.,:

a pivoted snap switch blade, a bi#metallic thermostaticlatch' 4having direct latching en gagement withsaidswitclifbladeland a sepal rate heater element for'saidr-latch .mounted in said recess zand-two terminal members mounted=onthe backof said body-.and elec-` trically' connected 'respectively to vsaid heater element and to the pivoted switch blade.

12. An electric cut-out comprising an insulating body having a recess in the front and a cradle opening in the back at each end, a terminal cap secured in each cradle behind said body, a stationary snap switch contact and a thermostatic latch mounted in said recess, a heater element in said recess having one end connected to said contact and a screw connecting the other end of said heater element to one of said terminal caps, a pivoted snap switch member in said recess adapted to co-act with the stationary contact and with the said latch and a screw connecting said snap switch member to the other terminal cap.

- 13. An electric cut-out comprising an in sulating block having a recess in the front and cradles in the back at opposite ends, a standard fuse cap secured in each cradle, stationary switch jaws, a heater element and a separate thermostatic latch mounted in said recess and connected to one of said caps, a pivoted snap switch blade mounted in said recess-and adapted to co-act with the sta" tionary .-jaws and with said thermostatic latchl and connected to theuother fusel cap said -latch having direct t operable engage- A ment with' said blade and being operable to release said blade circuit. t f 14. Anelectric` cut-out including alspring pressed switch member, astationary contact member and appurtenantternlinals for said prior tothe opening of the members, abi-metallic thermostatic latch having :direct Ioperable engagement with the spring lpressed switch; member and a heating element 'forthe latch, the .latch 4affecting portion nf said heating element being positioned along side of oneg'edge` of, said latch but -ree of directcontact ,withtsaid latch.: t

1.5.1 e1ectrie eut ont including a spring pressed switch :membenia .stationary contact memberv and; appui-,tenant terminalsfon saidl members,- -at bi-metallic` --therrnostatic .latch for the. spring4 pressed: switchtmember and a heating element fonthje latch, thel latch a1- fecting portionof said heating element being- 1. positioned adjacent:toa-said,flatoh.4 but entirelyout of the path of movementof said latch, whereby the Y normal f pperating movement of saidlat'ch zis ejiected\ mainly bythe heatv radiated from -said heating element.

ad 16. Anelectricl cut-out including aspring latch, whereby: thezvnormal' bending movement of said latch is not limited mechanically by the proximity of the said heating clement.v

17. An electric cut-out including a switch having a spring pressed contact, a co-operating stationary Contact and appurtenant terminals, a bi-lnetallic latch having direct abutting engagement with the pressed' contact and a heater element inseries with the latch, said spring pressed contact and said stationary Contact co-operating toy maintain a closed= circuit for an appreciable time after said latch has been released by said heater element.

18. In a switch. a rectangular body having a recess open at the front, a switch member pivoted in one end of the.. recess, a switch contact anda bi-metallic thermostatic latch secured in the opposite enda heater element mounted entirely behind the thermostatic member andy positioned away from the operating; path of saidlatclnat cover for `the recess, securing meansfor said cover, and termmalcaps on the back of the bodyl atl opposite ends and connected' respectively to said switch member and to said heater element.

19. A11 electric cut-out comprising an insulating housing having external terminals at the back and on opposite ends, a pivotcd springpressed switch blade mounted in said housing and electrically connected with one terminal, a stationary bracket detachably mounted in said housing, a contact and a thermostatic vlatch carried by said bracket; and removable therewith and a heater element having one endvsecured to said bracket and the other end secured electrically to the other terminal.

CLARENCE D. PLATT.

spring. 

